Seamers are used in the industry for closing beverage, food, and aerosol cans, as well as other enclosures such as oil drums, oil filters and even capacitor enclosures, before and after these containers are filled. Seaming the cans has been known in the industry for decades and ensures that the closure between the can's cover and the can's body is sealed and safe enough so that the content does not leak and outside hazards cannot enter the enclosure through the seams. There is no contact of heat, dirt, or hazardous materials with the contents of the enclosure by using seaming methods.
In present-day seamers, there are two phases during the seaming process. A chuck is a tooling that operates within the seamer and holds the can (a container or enclosure) in position while the seamer is turning. A first operation roll then approaches the can and pushes the body and cover into one another while rotation performs the operation around the circumference of the can. At this point, the first operation roll moves away and a second operation roll, with a different profile shape exerts pressure on the cover and body so that the final seam is tight enough and that it is sealed properly.
Seamers often have more than one head so that several cans can be closed simultaneously. Each one of the head's chuck and rolls are at intermediate positions during the seaming process.
With today's high speed manufacturing requirements, seamers as well as other procedures that take part in the filling and manufacturing of cans are expected to increase in speed. As speeds increase, there are more potential problems with the seams due to the inaccurate positioning of the tooling with reference to one another (one tooling against the other) during the seaming procedure.
Once a problem in a seamer is detected, the seamer must be completely stopped (all heads are affected) and the appropriate manufacturing head's tooling must be adjusted. The cans that were incorrectly seamed must be located and thrown away (most likely, it is too late and the cans manufactured by a particular head and many more than necessary are thrown away). The incorrectly positioned tooling must be quickly adjusted in order to continue the manufacturing process.
In addition, tight clearances, which are the distances between the chuck and rolls, may cause friction between the roll and the chuck and could cause one or the other to shatter—which might damage the seamer and possibly introduce dangerous material into the cans. Tight clearances might also exert unnecessary pressure on the seams, which could cause the seam to weaken, or even ultimately break, or be misshapen in a way that could damage the users (e.g., by scratching them).
Clearances that are not tight enough could cause an open seam, which might introduce hazards into the enclosure, or allow the contents of the enclosure to escape or be contaminated.
Small initial variations in the distances between the rolls and the chuck throughout the seamer heads will increase due to the pressures exerted on the tooling during the manufacturing process. Over time, the variations between the heads will increase substantially. This will result in subsequently having to stop the seamer several times, once for each head that has gone out of alignment, instead of once for all the heads.
Measurements of the distances between the toolings are done in the apex of the motion of the roll against the chuck. This is the point where the toolings are at the closest possible position to each other during the manufacturing process. The seamer manufacturer marks the specific position on the seamer (there is a range where the distance will not change, wherein this distance approximately equals the circumference of the can being seamed).
The state of the art methods of measuring tooling characteristics are as follows:    1. Measuring the thickness, which is the smallest distance through the range of motion between the roll and the chuck, by inserting feeler gauges (also known as filler gauges) between the roll and the chuck tooling. If a feeler gauge (larger than the specific distance) cannot be inserted between the tooling and a second feeler gauge (smaller than the specific distance) can be inserted between the tooling—the distance is assumed to be correct. This method is subjective as it is too difficult to accurately verify that the distance is within the specification after the use of feeler gauges.    2. Measuring the clearance, which is the vertical position of the chuck and the roll. The clearance is usually measured by measuring a point on the roll against a reference point. Then, the chuck's known position is measured against the same reference point (usually the can holder platform). The difference between the two measurements is a representation of the vertical distance between the roll and chuck. This method is complex and almost impossible to perform accurately as small inaccuracies on the roll itself or in the gauge can cause a major inaccuracy in the measurements. Both the clearance and thickness measurements are interactive—modifying one can easily alter the other, so measuring them and adjusting them individually, as it is done today, is incorrect and inaccurate.
This procedure must be carried out separately for the first and second operation rolls and the chuck for each head. The procedure is relatively long; thus stopping the manufacturing process for a relatively long period of time. At the same time, the procedure is prone to inaccuracies and disadvantages such as: mistakes in the first operation roll position are not apparent and can cause issues that are difficult if not impossible to detect and correct; Because of production requirements, it is often impossible to remove second operation rolls once they are installed (in order to reposition the first operation rolls); Experienced operators are needed; The procedure does not allow determination of the optimal positions of the rolls and chucks in order to produce correct seams; The procedure is expensive since many cans are thrown away; Finally, the procedure is extremely time consuming.
It is a long felt need to provide a method for measuring the distance between the tooling and the clearance that is efficient and quick. According to the present invention, use of an optical device is highly efficient and accurate as well as relatively quick and economical due to eliminating both the need to remove rolls and the need to throw away excessive amount of cans.
The use of optical devices for evaluating and inspecting surfaces, profiles, and dimensions is known in the industry. Devices that are relevant to the present invention are profilers. Profilers based on light projection are also known. An example is disclosed in patent U.S. Pat. No. 4,983,043 “High accuracy structured light profiler”, filed by Harding in 1988. This optical gauging system for evaluating the surface shape includes an illumination system which projects a line of light onto a work piece surface, a viewing system focused along that line. The focused line is imaged onto a linear detector array. A translation mechanism is also provided so that the relation between the translation mechanism and the output of the array is related to the profile shape. A method for measuring contours is disclosed in U.S. Pat. No. 5,612,786 “Contour measurement system” filed by Huber in 1995. The optical system is activated to obtain a set of data that is being optimized and calibrated so as to obtain the contours of a three dimensional object.
Another example of a profiler is in U.S. Pat. No. 5,986,745 “Co-planar electromagnetic profile scanner”, filed by Hermary in 1997. This co-planar system for determining the shape and dimensions of a surface of an object includes a projector, a receiving device and a discriminator for determining which portion of the reflected pattern corresponds to which portion of the projected pattern. The resulting signals and correlations are used to calculate the shape and dimensions of the object.
None of the above mentioned optical devices as well as other devices can be applied for determining the distance and clearance between the first and second operation rolls and the chucks of the present invention. There was a need to establish an optical device by which the distance between the tooling in the seamer can be accurately determined, while the chuck and the rolls are installed in the seamer.